Device for connecting and holding the rod fittings in two finished concrete parts, or the like

ABSTRACT

A device for placing in tension or compression opposed rod end fitting projecting from opposed concrete parts or the like comprises a coupling for connection to the rod ends and having swivel-connected parts with the center or centers of the swivel action intersecting the axes of the rod ends, and with screw thread means for expanding or contracting the effective length of the coupling between the rod ends to stress the same between the concrete parts.

United States Patent [1 1 Schmid DEVICE FOR CONNECTING AND HOLDING THE ROD FITTINGS IN TWO FINISHED CONCRETE PARTS, OR THE LIKE [76] Inventor: Josef Schmid, Liebnizstrabe 18,

8900 Augsburg 22, Germany [22] Filed: Feb. 1, 1973 [21] Appl. No.1 328,518

[30] Foreign Application Priority Data 403/43, 44, 46, 48, 77, DIG. 8; 24/116 A, DIG. 21; 52/223, 227, 230

[56] References Cited UNITED STATES PATENTS 141,191 7/1873 Wilson 403/43 407,559 7/1889 Wells 403/44 [45 1 Jan. 7, 1975 2,524,894 10/1950 Dobrin 403/77 2,905,491 9/1959 Olson r 403/44 3,089,215 5/1963 Stubbs 254/29 A 3,143,365 8/1964 Egger i 403/77 3,329,454 7/1967 Melton 403/77 3,405,490 10/1968 La Marr 1 254/29 A 3,583,052 6/1971 Herbenar 403/43 Primary Examiner-Al Lawrence Smith Assistant Examiner-Robert C. Watson Attorney, Agent, or Firm-Burton & Parker [57] ABSTRACT A device for placing in tension or compression opposed rod end fitting projecting from opposed con crete parts or the like comprises a coupling for connection to the rod ends and having swivel-connected parts with the center or centers of the swivel action intersecting the axes of the rod ends, and with screw thread means for expanding or contracting the effective length of the coupling between the rod ends to stress the same between the concrete parts.

5 Claims, 12 Drawing Figures PATENI JAN 7197s SHEET 1 OF 5 will! 'PATENTED JAN T1975 SHEET 2 UF 5 FATENTEUJM Yrss SHEET '4 OF 5 PATENTEU JAN 7 I975 SHEET 5 [IF 5 DEVICE FOR CONNECTING AND HOLDING THE ROD FITTINGS IN TWO FINISHED CONCRETE PARTS, OR THE LIKE FIELD OF INVENTION This invention relates to devices for tensioning toward each other or repelling away from each other con crete parts, such as concrete supports, or the like, and in particular devices adapted to be connected to rod ends projecting from such concrete parts for effecting the same.

BACKGROUND OF THE INVENTION It is often necessary or desirable in construction work to connect together spaced, finished, concrete parts, such as supports, either by tensioning the concrete parts toward each other or imposing a force tending to push them apart. Conveniently this connection may be effected by engagement of metal rod ends such as iron or steel anchored in the concrete supports and projecting from the supports toward each other. Generally such rod ends are not in perfect alignment but are offset slightly or may angularly intersect or be askew. Because of such displacement, difficulty is encountered in quickly, easily, and effectively utilizing the rod ends as anchor points for tension or compression devices.

One approach to solving this problem is shown in West German Offenlegungsschrift No. 1,784,807 which utilizes eccentric, threadedly connected parts.

, However the device must be of a large diameter to be effective over any appreciable range of rod end misalignment, which materially adds to its weight, and it is of rather complicated construction. Additionally, the rod ends must be disposed in relatively close proximity and cannot lie on angularly intersecting or askew axes. Furthermore, the transfer of load between the rod ends involve substantial localized sheer forces as such forces are not transmitted along the axes of force transmitting members which intersect the axes of the rod ends.

There is a need for a simplir and better solution to the problem of connecting the rod ends, which will allow connecting them when they are at varying distances, sometimes considerable distances from each other, when they are askew or their axes intersect, and without causing an abrupt change in direction or lateral displacement of the lines of force between the rod ends.

SUMMARY OF THE INVENTION A number of the embodiments of the invention are disclosed herein. Where the rod ends are in substantial alignment, a pair of sleeves having right and left hand threads at opposite ends are threaded with a common hand thread onto the tie rod ends, and a bolt having threads at opposite ends is threadedly connected between the sleeves to either place the rod ends in tension or compression. But except for this special case which is not often found in practice, the preferred embodiments of the invention are adapted for use with rod ends whose axes are displaced or angularly intersect or are askew. The preferred embodiments utilize a coupling having swivel-connected parts with the center or centers of the swivel intersecting the axes of the rod ends. Screw thread tensioning or compressing means in the coupling serves to stress the rod ends through the coupling.

Where the axes of the rod ends intersect, the invention contemplates a ball joint on one rod end with a socket retained on the ball and having an internal thread for engagement with the other rod end. By rotating the socket to thread it in the cooperating rod end the joint, and consequently the two rod ends, may be tensioned.

Where the axes of the rod ends do not intersect, either because they are simply laterally displaced, though parallel, or they are oblique, the invention discloses a pair of ball joints at each rod end connected by a bolt means threaded at each end for threaded engagement with the joints. By relative rotation between threadedly connected parts the assembly may be placed in tension. Through modifications in the balll joints the assembly may be placed in compression.

In another embodiment, also for non-intersecting rod ends, instead of a ball joint there is disclosed what may be termed a threaded eccentric swivel at each rod end with bolt means extending therebetween for placing the rod ends in tension or compression. Each swivel includes an outer sleeve connected to an end of the bolt means and internally threaded along an oblique axis at the opposite end. An internal sleeve having obliquely arranged internal and external threads is screwed into the sleeve and on to the rod end. By suitable relative rotation between the internal sleeve, external sleeve and rod end, the axis of the bolt means may be arranged to intersect the axes of the rod ends to be joined. The bolt means is provided with a connecting sleeve and suitable right and left hand threads whereby the entire assembly may be subjected to compression or tension.

The invention has particular utility where the rod ends are rigidly anchored in the concrete parts and their axis are non-intersecting.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a longitudinal section of a first embodiment of the device according to the invention, prior to assembly;

FIG. 2 shows the device according to FIG. I, in the installed position;

FIG. 3 shows a longitudinal section of a second embodiment of the device according to the invention;

FIG. 4 shows a longitudinal section ofa third embodiment, before assembly with the rod ends;

FIG. 5 shows the device according to FIG. 4, in the installed position;

FIG. 6 shows a longitudinal section of a fourth embodiment of the device according to the invention;

FIG. 7 shows the device according to FIG. 6, in an angular setting;

FIG. 8 shows in longitudinal section a modification of the device according to FIGS. 6 and 7;

FIG. 9 shows a longitudinal section of a fifth embodiment of the invention in the installed position, wherein the connected rod ends are not in alignment;

FIG. 10 shows the embodiment according to FIG. 9, after installation, to connect two rod ends which are in alignment;

FIG. 11 shows a detail of FIGS. 9 and 10, on a larger scale; and

FIG. 12 shows in longitudinal section another, simplified embodiment of the invention.

BRIEF DESCRIPTIONOF PREFERRED EMBODIMENTS In FIGS. 1 and 2 the rod ends I and 2 of rod fittings project from finished concrete parts (not shown), as from the frontal faces of supports or the like. After the concrete finished parts have been installed or implaced, the rod ends 1 and 2 cannot be displaced, that is they can not be shifted nor turned. Spherical heads and 4 are fastened to the rod ends 1 and 2. For example, the heads 3 and 4 can be formed integrally with rod sections 5 and 6 which, in turn, are fastened to the rod ends 1 and 2, respectively, by butt welding. Also, there are sleeves 8 and 9, each of which fits over one of the spherical heads 3 and 4 with the retracted part, 10 and 11. In the embodiment shown, the design is such that the sleeves 8 and 9 are fitted over the respective spherical heads 3 and 4, before the corresponding buttweld, indicated by 7. In the design according to FIGS. 1 and 2, each sleeve 8 and 9 has an internal thread 12 and 13 which can be screwed together with the corresponding threaded end 14,15 of connecting rod means in the form of at least one threaded bolt 16, disposed between the sleeves 8 and 9. The threads 12 and 13 can be of the same, or opposite hand, as desired.

The diameter f of spherical heads 3 and 4 is smaller than the diameter g of threads 12 and 13 in sleeves 8 and 9, such that the sleeves can be displaced axially over the spherical heads 3 and 4. This has the advantage that the sleeves 8 and 9 can be screwed onto the respective threads 12 and 13 of threaded bolt 16, completely independently of one another, so that the kind of matching of threads is not critical; that is, the pair of threads 12, 14 is independent of thread pair 13, 15, both in angle of pitch and in diameter. Because of the spherical heads 3 and 4, which are mounted pivot-wise in the sockets 17 and 18, formed by the retracted parts 10 and 11, deviations of the rod ends 1 and 2 from a common axis can be equalized, insofar as sufficient play is left between the retracted parts 10 and 11 and the rod ends 1 and 2. In FIGS. 1 and 2 the rod ends 1 and 2 are shown in alignment, merely for the sake of simplicity. It is evident that, with this design, only tension can be exerted on the rod ends 1 and 2.

If, in addition, a compressive stress is to be applied, the second embodiment according to FIG. 3 should be used. In this case the threaded sleeve 20 screws into the sleeve 8 by means of its external thread 21 which, toward the spherical head 3', has a base 19 which makes contact with the spherical head. This threaded sleeve also has an internal thread 22. On threaded section 23 of a doubly threaded nipple 24 is screwed into internal thread 22. Furthermore, there is a third threaded sleeve 25 which connects the doubly threaded nipple 24 with the threaded bolt 16'.

As may easily be seen, compressive forces or stresses between rod ends 1' and 2' can be generated with this design, as soon as the base 19 bears against the spherical head 3'. It is sufficient that the sleeve 8' be turned while the threaded bolt 24 is held fast. However, with the embodiment shown, the threaded sleeve 20 has an outer thread 21, which naturally differs from the inner thread 22, and therefore a stress can be developed merely by turning the threaded sleeve 20, said turning being effected by means of a (not shown) molded-on hexagon, projecting beyond the sleeve 8, and a suitable wrench. In the embodiments of FIGS. 1-3 the center of each pair of swivel-connected parts is defined by the balls 3, 4 and 3', 4i and these of course intersect the axes of the rod ends 1, 2 and 1, 2.

In the preceding description it was assumed that the device shown in FIG. 3 to the left of the break a is repeated at the other rod end 2'. However, the variant actually shown to the right of break a in FIG. 3 can be used, making possible the omission of the threaded sleeve 20. There the threaded sleeve 9' is fashioned with a partition or wall 26, the right side of which bears against the spherical head 4. In order to obtain the most favorable load distribution possible between the threaded sleeve 9 and the spherical head 4, this partition is designed 27 to be shaped as shown, in order to provide two points of contact between the wall and the sphere. It is evident that, with this design, the sphere 4' must be placed in the appropriate recess, before the rim is contracted at 28.

In the next embodiment according to FIGS. 4 and 5, as well as that according to FIG. 3, the symbols used are those which, as far as possible, confirm to those used in FIGS. 1 and 2. Here, too, rod ends are shown which are joined to rod sections 5 and 6 by butt welding; these have spherical heads 3 and 4 disposed on them. The rod ends 1 and 2 and the rod sections 5 and 6 are substantially aligned coaxially, but they may also be displaced parallel to one another or be disposed askew.

Again there are two threaded sleeves 8 and 9, the internal threads 12 and 13, of which can be screwed to gether with the corresponding threaded ends 14 and 15 of at least one threaded bolt 16, installed between the sleeves 8 and 9.

Each constricted rim part 10, 11 now has a sphericalshell-like concave socket l7, 18 as the contact surface for the respective spherical head 3, 4, with a radius which is at least equal to the radius of the corresponding spherical head; in addition, each threaded sleeve 8, 9 has two lock nuts 29, 30 and 29', 30'. The lock nuts 29 and 29 are mounted on the threads 31 and 32 with which the rod sections 5 and 6 are provided. The lock nuts 30 and 30, on the other hand, are mounted, respectively, on threads 14 and 15 of threaded bolt 16. As may readily be seen, the lock nuts 29, 29', in the as sembled disposition of the device, can be screwed up against the corresponding constricted rim parts 10 and 11 of the threaded sleeves 8 and 9, as the result of which a compressive stress can be developed between the two rod ends 1 and 2, the rod sections 5 and 6, via the lock nuts 29, 29', the constricted rim parts 10 and 11 and thus threaded sleeves 8 and 9 and, finally the threaded bolt 16. Naturally, this all is merely a matter of the relative tightening of the lock nuts 29, 29' and the sleeves 8 and 9. The purpose of the lock nuts 30, 30' is to secure the threaded bolt 16 with respect to sleeves 8 and 9; these lock nuts come into contact with their faces 31' and 32'.

FIG. 5 shows the setting of the device when installed, with washers 33, 33' and 34, 34', respectively, placed between the lock nuts 29, 29' and 30, 30' and the threaded sleeves 8 and 9, for the purpose, particularly, of protecting the bearing surfaces of sleeves 8 and 9.

As may easily be seen, the use of lock nuts makes it possible, in a very simple manner, to create a device which, is also able to transmit compressive stresses.

In order to be able to equalize a parallel displacement or an askew position of the longitudinal axes of the rod ends, the threaded sleeves should be able to be tilted about the spherical heads, with respect to the rod ends. In the particularly preferred embodiment shown in FIG. 6, the necessary play is provided between the constricted rim part and rod end 1 and the welded-on rod section 5 by trunco-conical opening 38, concentric with the longitudinal axis 36 of threaded sleeve 37, the surface 39 of which has the periphery of rod section 5 as generatrix. Thus the opening 38 forms a truncated cone which allows the rod section 5 to swing in all directions about the center 40 of the spherical head 41, until the periphery of the rod section 5 makes a linear contact with the external surface 39 of the opening 38. This design provides the greatest possible surface of contact between the spherical head 41 and the con stricted rim part 35 of the threaded sleeve 37 on the one hand and, on the other hand, at the same time the greatest possible pivotability of the threaded sleeve 37 with respect to the rod section 5. This is due to the fact that the trunco-conical opening 38 faces the spherical head 41 with its smallest diameter and faces the other side with its largest diameter. In the preferred embodiment shown, the surface 43 of the contracted rim part 35, facing the corresponding lock nut 42, is spherically convex and is disposed concentric with the spherically concave socket 44.

Expediently, a washer 45 is placed between the spherically convex surface 43 of the constricted rim part 35 and the corresponding lock nut 42, the surface 46 of this washer, facing the threaded sleeve 37, being spherically concave with a radius which corresponds to the convex surface. It is evident that the spherically concave surface 46 may also be fashioned on the lock nut 42; however, as was pointed out above, it is better to use washers.

FIG. 7 shows the embodiment according to FIG. 6, in a pivoted position, that is when there is an angle a between the longitudinal axis 36 of the threaded sleeve 37 and the longitudinal axis 36 of rod section 5, or rod end 1. This figure shows particularly clearly the changed position of the constricted rim part 35 in relation to the spherical head 41 and the washer 45. The pivotal point is obviously the center 40 of the spherical head. The contact, on all sides, of the washer 45 with the convex surface 43 of the constricted rim part 35 illustrates the attainable, relatively uniform, transfer of force. Also, in the embodiments according to FIGS. 6 and 7 (in which, in each case, only half the device is shown) lock nuts 30 and washers 34, used to secure the threaded sleeve 37 at the threaded end-14 of threaded bolt 16, are shown.

As may also be seen from FIG. 8, the spherical head need not necessarily have a strictly spherical shape; rather, it may be in the form of a cap 47 with adjoining cylindrical part 48.

It should be pointed out that it is not absolutely necessary that rod sections 5 or the like, with threads 31, be welded onto the ends of the rod fittings. Rather, this thread can be cut in advance on rod ends 1 and 2 of the fittings. In the embodiment according to FIGS. 6 and 8, the spherical head 41, 48 is screwed onto the thread 31 and, preferably, is shrunk on, which assures a firm, undisplaceable, mounting of spherical head 41. It will be noted in studying the embodiments of FIGS. 4-8 that in each instance the center of the swivel action, which is defined as the center of the spherically shaped parts 3, 4 and 41, or the center from which the spherical surface on part 4-8 is generated, intersect the axis or axes of the adjacent rod ends.

In the embodiments which follow, described in the light of FIGS. 9 to 11, the rod ends 1 and 2 of the rod fittings of two (not shown) finished concrete parts have equivalent threads 50 and 51. The longitudinal axes, and at the same time the thread axes, 52, 53 of rod ends 1 and 2 are spatially askew and cannot be displaced or turned. Threaded sleeves 54 and 55 are disposed on them. In addition, there are also another threaded sleeve 56 and two threaded bolts 57 and 58.

As may be seen in FIG. 9, threaded sleeves and the threaded bolts alternate. The end sections of the sleeves 54 and 55 adjacent the rod ends 1 and 2 (which sleeves are sometimes herein referred to as outer sleeves) have internal threads 59 and 60 whose axes 63 and 64 respectively angularly intersect the longitudinal axes 61, 62 of the sleeves. In addition, one of these sleeves, for example sleeve 55, has in its opposite end section a lefthanded thread 65 cooperating with threaded bolt 58, it being assumed that the rod ends 1 and 2 have right-handed threads. A third threaded sleeve 56, fashioned like a turnbuckle, has left and right-handed threads 66, 67 and screws onto the threaded bolts 57 and 58, on both sides. As is quite evident from FIG. 9, the device has left-handed threads in region a which includes both thread pairs, threaded sleeve 56 and threaded bolt 58, and threaded bolt 58 with sleeve 55, while the remaining thread pairs, that is sleeve 54 with thread section 68 and threaded bolt 57, on the one hand, and threaded bolt 57 and sleeve 56 with section 67, on the other hand, have righthanded threads in region b. Also threads 59 and 60 are right-hand. Each threaded section 59, 60 which has a thread axis 63, 64 which angularly intersects the longitudinal axis 61 and 62 of the respective sleeves 54 and 55 is not screwed directly onto the corresponding rod end 1 and 2, but rather through an intermediate sleeve 69, 70. Each of the respective intermediate sleeves 69, 70 has an internal thread 71, 72 corresponding to the rod end 1 and 2, and an external thread '73, 74 corresponding to the threaded section 59, 60 of threaded sleeve 54, 55. Also, the two thread axes 75 and 76 of the internal and external threads angularly intersect as is shown in FIG. 11. As illustrated, the angle of intersection between the internal and external threads of the intermediate sleeve is equal to the angle of intersection between the axis of the internal threads in the projecting end of the outer sleeve and the axis of the connecting rod assembly. Since, in the device shown, the intermediate sleeves are identical, a description of one will suffice for both, and in FIG. 11 I have shown sleeve 69.

As may easily be seen from the drawing, any desired angle between rod ends 1 and 2, on the one hand, and the neighboring, mutually coaxial, threaded bolts 57, 58, on the other hand, may be set, namely continuously, within the limits determined by the angle a between thread axes 75, 76 of the inner and outer threads of the intermediate sleeves and by the acute angle B between the two thread axes of the respective threaded sleeves for example axes 62 and 64 of sleeve 55. For this purpose, it is merely necessary to turn the respective intermediate sleeve 69, 70 and the respective sleeve 54, 55 relative to one another. FIG. 9 shows the greatest possible bending, with angles a and B being added together. Suitably these two angles are equal to each other. It should be noted that, in the installed position, the thread axes 75 of the intermediate sleeve and the longitudinal axes 52 and 53 of the rod ends 1 and 2, as well the thread axes 76 of the intermediate sleeve and the thread axes 63 and 64 of the sleeves 54 and 55 coincide. Thus, as in the preceding embodiments, the effective centers of the swivel action, afforded by the threaded assembly of intermediate sleeves 69 and 70 within the outer sleeves 54 and 55, intersect the axes of the rod ends.

FIG. 10 shows a setting of the embodiment of FIG. 9 in which the angles a and B completely nullify one another, thus making possible a connection between rod ends I and 2' which are in alignment. This illustrates the adaptability of this'embodiment to rod end alignment or misalignment as in the cases of the previously described embodiments.

As has already been stated, this adaptability is accomplished by turning the intermediate sleeve relative to the outer sleeve; however, the direction of the deflection is determined by turning the intermediate sleeve and the outer sleeve as a unit about the respective rod end.

In FIG. 10 the face 77 and 78 of the respective intermediate sleeves is perpendicular to the thread axis 75 of the internal thread, and the face 79 and 80 of the outer sleeve 54 and 55 is perpendicular to thread axis 63 and 64. This makes it possible, on the one hand, to provide lock nuts 81 and 82 on rod ends 1 and 2 to lock intermediate sleeves 69 and 70, and to provide lock nuts 83 and 84 on the intermediate sleeves to lock them against the outer sleeves. Between the threaded bolts 57 and 58 and the threaded sleeves 54 and 55 there also are lock nuts 85 and 86 so that these parts may also be locked. Between the threaded bolts 57, 58, on the one hand, and the threaded sleeve 56, on the other hand, locking is possible without lock nuts, in that both threaded bolts (as indicated at 87) are allowed to bear against one another, since threaded sleeve 56, practically speaking, is a turnbuckle with right and left threads. FIG. 10 also shows in perspective frontal views of the intermediate sleeve 69 and the threaded sleeve 54 to illustrate the respective oblique inner threads 71 and 59.

The various threaded elements and threaded sleeves and threaded bolts as well as the intermediate sleeves may be fashioned with contact surfaces for wrenches or the like, to facilitate turning the individual parts with respect to one another, but in the interest of simplifying the drawings these are not shown in detail.

Furthermore, it has been found to be expedient and sufficient to make the angles a and B about degrees.

Installation of the device shown in FIGS. 9 and 11 takes place as follows: First, the outer sleeves 54 and 55 are installed over the intermediate sleeves 69 and 70 at rod ends I and 2 and are so adjusted that their threads 62 and 63 are aligned with one another. Then, on the one hand, the threaded bolt 57 is screwed into the right-handed thread of sleeve 54 and, on the other hand, threaded bolt 58 into the left-handed thread of sleeve 55. Then, threaded sleeve 56 is placed between the threaded bolts and is screwed together with them. If the bolts 57 and 58 are to have a distance between them inside the sleeve 56, perhaps in order to be able to create a compressive or tensile stress, additional lock nuts (not shown) should be provided for bearing against sleeve 56.

It should be noted that the portion of the device located to the right of line A in FIG. 9 may, in some cases, suffice to provide a connection between the rod fittings, namely when the ends of the rod fittings to be connected are not askew with reference to one another, but intersect. It should be noted that, in that event, the threaded bolt 57 is to be considered as one rod end.

It is expressly pointed out that, in some cases, it may be necessary to make the sleeve 56 longer in order to assure a better opportunity for mounting the threaded bolts in the threaded sleeves as will be apparent to those skilled in the art.

In the event that at least one rod end is displaceable, there is no need for a left-handed thread. For example, such displaceability is provided when ring fittings for round receptacles are to be made. While such annular fittings are bent into a ring from a single rod, one cannot avoid having the two rod ends of such annular fitting stretched and thus they will come together at an angle. This case also corresponds to the case shown in FIG. 9 to the right of the line A, where in the region a right-handed threads would be used. For example, due to the displaceability of the end of rod fitting 57, the connection can always be screwed together, it also being possible to make the threaded bolt 58 and the sleeve 55 in one piece, thus eliminating thread 65.

FIG. 12 shows a simplified device according to the invention, intended to be used to connect two fitting ends l" and 2", which align with one another. Only one threaded bolt 88 need be provided; this has a lefthanded thread (assuming that the rod ends I" and 2" have right-handed threads). There are only two threaded sleeves 89 and 90, both fashioned like turnbuckles and having left-handed threads in the regions designated by c. The connection is made in that first the threaded sleeves 89 and 90, with right-handed threads, are screwed onto the rod ends 1 and 2" and the threaded bolt 88 then is screwed into one sleeve and then the threaded bolt 88 and the threaded sleeves 89 and 90 are screwed together until the free end of threaded bolt 88 can engage the corresponding threaded sleeve.

It should be pointed out that, naturally, it is possible to fashion the threaded section 68 of the sleeve 54 as a bolt; bolt 57 then becomes a sleeve, sleeve 56 becomes a bolt, bolt 58 a sleeve and the threaded section 62 of sleeve 55 becomes a bolt. To those skilled in the art, changes of this type will be apparent.

What is claimed is: i

l. A device for connecting and stressing rod ends projecting from opposed fixed supports comprising, in combination:

a connecting rod assembly including a pair of connecting rod elements arranged end-to-end,

sleeve means connecting the rod elements together and operable upon relative rotation between the sleeve means and the rod elements to vary the overall effective length of the assembly,

swivel joints at opposite ends of the connecting rod assembly, and each joint being connected to one of the projecting rod ends with its center of swivel movement aligned with the axis of the projecting rod end, the swivel joints including outer sleeves are threadedly connecting the opposite ends of the connecting rod assembly in coaxial alignment and project therebeyond, threaded bores in the projecting ends of the outer sleeves having bore axes angularly intersecting the axis of the connecting rod assembly, and

the swivel joints further comprising an intermediate externally threaded sleeve screw-engaged within the projecting end of each outer sleeve, each intermediate sleeve having an internally threaded bore whose axis is inclined to but intersects the axis of its external threads and said bore being threadly connected to external threads on the adjacent projecting rod end.

2. The invention defined by claim 1 characterized in that the angle of intersection between the internal and external threads of the intermediate sleeve is equal to the angle of intersection between the axis of the internal threads in the projecting end of the outer sleeve and the axis of the connecting rod assembly.

3. The invention defined by claim 2 characterized in that lock-nut means are mounted on the connecting rod elements to bear against the outer sleeves and are mounted on the external threads of the intermediate sleeves to bear against the opposite end of the outer sleeve and are mounted on the external threads of the projecting rod ends to bear against the intermediate sleeves.

4. The invention as defined in claim 3 characterized in that said sleeve means is provided with internal right and left-hand threads and the confronting ends of the end-to-end arranged connecting rod elements are provided with corresponding threads.

5. The invention as defined in claim 1 characterized in that said sleeve means is provided with internal right and left-hand threads and the confronting ends of the end-to-end arranged connecting rod elements are provided with corresponding threads. 

1. A device for connecting and stressing rod ends projecting from opposed fixed supports comprising, in combination: a connecting rod assembly including a pair of connecting rod elements arranged end-to-end, sleeve means connEcting the rod elements together and operable upon relative rotation between the sleeve means and the rod elements to vary the overall effective length of the assembly, swivel joints at opposite ends of the connecting rod assembly, and each joint being connected to one of the projecting rod ends with its center of swivel movement aligned with the axis of the projecting rod end, the swivel joints including outer sleeves are threadedly connecting the opposite ends of the connecting rod assembly in coaxial alignment and project therebeyond, threaded bores in the projecting ends of the outer sleeves having bore axes angularly intersecting the axis of the connecting rod assembly, and the swivel joints further comprising an intermediate externally threaded sleeve screw--engaged within the projecting end of each outer sleeve, each intermediate sleeve having an internally threaded bore whose axis is inclined to but intersects the axis of its external threads and said bore being threadly connected to external threads on the adjacent projecting rod end.
 2. The invention defined by claim 1 characterized in that the angle of intersection between the internal and external threads of the intermediate sleeve is equal to the angle of intersection between the axis of the internal threads in the projecting end of the outer sleeve and the axis of the connecting rod assembly.
 3. The invention defined by claim 2 characterized in that lock-nut means are mounted on the connecting rod elements to bear against the outer sleeves and are mounted on the external threads of the intermediate sleeves to bear against the opposite end of the outer sleeve and are mounted on the external threads of the projecting rod ends to bear against the intermediate sleeves.
 4. The invention as defined in claim 3 characterized in that said sleeve means is provided with internal right and left-hand threads and the confronting ends of the end-to-end arranged connecting rod elements are provided with corresponding threads.
 5. The invention as defined in claim 1 characterized in that said sleeve means is provided with internal right and left-hand threads and the confronting ends of the end-to-end arranged connecting rod elements are provided with corresponding threads. 